A hybrid local search algorithm for consistent periodic vehicle routing problem

Under consideration is some new real-world application of vehicle routing planning in a finite time horizon. Let a company have a set of capacitated vehicles in depots and serve a set of customers. There is a frequency for each customer which describes how often the customer should be visited. Time intervals between two consecutive visits are fixed, but the visiting schedule is flexible. To obtain competitive advantages, the company tries to increase the service quality. To this end, each customer should be visited by one driver only. The goal is to minimize the total length of the vehicle paths over the planning horizon under the frequency constraints and driver shift length constraints.
We present a mixed-integer linear programming model for this new consistent capacitated vehicle routing problem. To find near optimal solutions, we design the variable neighborhood search metaheuristic with several neighborhood structures. The driver shift length and capacitated constraints are penalized and included into the objective function. Some numerical results for the real-test cases are discussed. Tab. 6, illustr. 1, bibliogr. 28.